Drive and steering units



July 16, 1968 J, SANDERS 3,392,603

DRIVE AND STEERING um'rs Filed Nov. 14. 1966 2 Sheets-Sheet 1 mvemon RAYMONIZ J. SANDERS J y 1963 R. J. SANDERS DRIVE AND STEERING UNITS 2 Sheets-Sheet 2 Filed Nov. 14, 1966 mvzm'aa RAYMOND J. SANDERS United States Patent 3,392,603 DRIVE AND STEERING UNITS Raymond J. Sanders, Vancouver, British Columbia, Canada, assignor to British Columbia Research Council, University of British Columbia, Vancouver, British Columbia, Canada Filed Nov. 14, 1966, Ser. No. 593,787 9 Claims. (Cl. 74720.5)

This invention relates to drive and steering units particularly for boats, but which may be used anywhere where it is desired to transfer power from a power shaft to a take-off shaft while permitting the latter to swing around an axis perpendicular to said shafts.

As this apparatus was primarily designed for use in boats, it will for the sake of convenience be described in this setting.

Small boats are used today to sort logs floating in the water, and it is desirable to be able to move these boats in any direction without having to turn them for this purpose. In other words, full 360-degree steering is required. This has been accomplished in the past by using a marine outboard motor mounted in a vertical central well in the hull of the boat. By manually rotating the unit about the vertical axis of the well, full 3'60-degree steering was achieved. Due to the short life of these outboard motors in this operation, attempts have been made to use diesel engines of suitable size as power plants for these boats.

One of these designs used two right-angle gear boxes, with a vertical connecting shaft, steering being achieved by rotating the lower gear box carrying the propeller about the axis of the vertical shaft. This was not a successful solution as the main drive torque overcame the steering torque, and rotated the gear box around its vertical axis. Power steering might have solved the problem, but it was not considered practical.

A method commonly employed of driving the propeller without affecting the steering is to use a hydraulic motor to drive the propeller direct, with the engine driving a suitable hydraulic pump, the two being connected by concentric tubes, provided with swivel joints. However, the hydraulic components are expensive, and difficult to protect from the effects of the marine environment. In addition, these components can only be overhauled and serviced in special facilities, and expensive precision spare parts must be kept in hand.

An object of the present invention is the provision of drive and steering units capable of providing 360-degree steering and which are very simple and economical in construction, comparatively light in weight, and easily maintained.

Another object is the provision of 3'60-degree drive and steering units which may be used with relatively high power without putting undue strain on the components thereof.

A drive and steering unit according to the present invention comprises a differential mounted for rotation around an axis, and differentially rotatable control and drive shafts projecting in opposite directions on said axis from the diflerential. A power shaft is connected to the differential to rotate it, said shaft usually extending substantially perpendicular to said axis. A take'otf shaft is mounted for angular movement in a plane around this axis, and drive means interconnects the drive and takeoff shafts. Steering means connected to the control shaft and to the take-off shaft normally prevents normal rotation of the control shaft and is operable to permit the control shaft to rotate and to cause angular movement of the take-otf shaft around the axis. When the differential is rotated by the power shaft and the control shaft is held against rotation, the drive and take-off shafts are rotated. Means is provided for counterbalancing normal torque of the control shaft. The apparatus is such that when the steering means is operated, the take-ofi shaft is swung around the axis of the drive shaft without affecting the transfer of power from the power shaft to said take-off shaft.

Three forms of the present invention are illustrated, by way of example, in the accompanying drawings, in which,

FIGURE 1 is a vertical section through a preferred form of drive and steering unit,

FIGURE 2 is a section taken on the line 22 of FIGURE 1,

FIGURE 3 is a section taken on the line 3-3 of FIGURE 1,

FIGURE 4 is a fragmentary view similar to FIGURE 1 illustrating an alternative form of drive and steering unit, and

FIGURE 5 is a fragmentary view of another alternative form of drive and steering unit.

Referring to FIGURES 1 to 3 of the drawings, 10 is a drive and steering unit according to this invention which includes a casing 11 which houses the main driving com ponents of this unit. A power shaft 12 which is adapted to be connected to a suitable source of power, such as an engine, not shown, extends into casing 11 and has a drive pinion 14 fixedly mounted on its inner end, said pinion meshing with a crown gear 16 of a differential 17. This differential includes a case 19 having axially aligned and differentially rotatable control and drive shafts 21 and 22 projecting outwardly in opposite directions therefrom, said shafts being on a common axis 23. This axis extends substantially perpendicular to the axis of power shaft 12, and when the apparatus is used in a boat, axis 23 is usually arranged vertically. Side gears 25 and 26 are respectively mounted on shafts 21 and 22 in differential case 19, and mesh with spider pinions 28 and 29 rotatably mounted on a shaft 30 extending across and secured to case 19 between said side gears. With this arrangernent, when power shaft 12 is rotated and control shaft 21 is prevented from rotating, drive shaft 22 rotates in the same direction as crown gear 16 but at twice the speed. Referring to FIGURE 1, when shaft 12 rotates in the direction of arrow 32, shaft 22 rotates in the direction of arrow 33.

A planetary epicyclic gear unit 36 is operatively connected to crown gear 16. In this example, the internal gear 38 of unit 36 extends around but is clear of drive shaft 22, and is fixedly connected to crown gear 16 in any suitable manner, as indicated at 39. A tubular shaft 41 surrounds drive shaft 22 and projects upwardly into the planetary unit 36. A sun gear 42 fixedly connected to shaft 41 meshes with a plurality of planet gears 44 which are rotatably carried by a spider 45, said gears 44 also meshing with internal gear 38. With this arrangement, if internal gear 38 and sun gear 42 have a diametric ratio of 2 to 1, with spider 45 held against rotation, tubular shaft 41 rotates at twice the speed of crown gear 16 but in the opposite direction, said direction being indicated by arrow 47 in FIGURE 1.

A tubular housing 50 surrounds shafts 22 and 41 and extends downwardly from casing 11. Housing 50 is rotatably supported at its upper end by a bearing arrangement indicated at 51, said arrangement being secured to and suspended from the bottom of casing 11. A gear box 53 is secured to the lower end of tubular housing 50, and shafts 22 and 41 project into this box. Shaft 22 extending downwardly in the gear box is connected to a pinion 55 which meshes with an idler pinion 56 mounted on a shaft 57 carried by said box and with an opposed drive pinion 58 mounted on the inner end of a power takeoff shaft 60 which is journalled in a bearing 61 and extends outwardly from box 53 substantially normal to axis 23. In this example, a propeller 64 is fixedly mounted on the outer end of shaft 60. Tubular shaft 41 extends into gear box 53 and is fixedly secured to a rotatable pinion 66 surrounding and clear of shaft 22 and meshing with pinions 56 and 58 in the gear box, said pinion 66 being opposed to pinion 55.

As stated above, shafts 22 and 41 rotate in opposite directions, but they apply their power through pinions 55 and 66 to drive pinion 58, rotating the latter and, consequently, take-off shaft 60 and propeller 64. With this arrangement, the engine torque is equally divided between and transmitted by the two counter rotating concentric shafts 22 and 41. The equal and opposite torques result in zero imbalance torque about the vertical steering axis 23.

When control shaft 21 and spider 45 are held stationary, power shaft 12 and output shaft 60 will always have the same angular relationship about axis 23. However, control shaft 21 and spider 45 must provide the necessary reaction torque to make differential 17 and planetary unit 36 function. If either the control shaft or the spider is rotated, the angular relationship of take-off shaft 60 to power shaft 12 will be changed, and this is utilized to provide the steering means for the boat in which unit is mounted.

A rotatably mounted steering shaft 68 is provided adjacent differential 17 and planetary unit 36, and projects outwardly out of casin 11. This shaft is connected to suitable manual or power steering means in any desired manner, such as by means of a sprocket 70 mounted on the upper end of shaft 68 and a chain 71 connecting the sprocket to the steering means, not shown.

A gear 72 fixedly mounted on control shaft 21 outside differential case 17 meshes with another gear 73 fixedly mounted on shaft 68. Another gear 75 surrounds shafts 22 and 41 and is fixedly connected to spider 45 to rotate therewith. Gear 75 meshes with an idler gear 76 which, in turn, meshes with a gear 77 fixedly mounted on steering shaft 68.

Control gear 72 and spider gear 75 require different torque reactions, acting in the same direction, to hold them and shaft 21 and spider 45, against rotation. The gear ratios for gears 72, 73 and gears 75, 76 and 77 are selected to provide the required torques to produce the required reaction for the control shaft and the spider.

Steering shaft 68 normally has zero net torque, and when it is rotated, gears 72 and 75 are rotated, and this results in the changing of the angular relationship of power shaft 12 and take-off shaft 60. If the correct gear ratios are used between shaft 68 and gears 72 and 75, not only will the torque reactions balance, but there can be a one-to-one ratio between the movement of shaft 68 and the resultant movement of take-off shaft 60 about the axis 23. Thus, rotation of shaft 68 steers the boat in which unit 10 is mounted.

One of the advantages of unit 10 is that pinion 14 and crown gear 16 are the only elements that have to be made strong enough to take full power. Each of the counter rotating shafts 22 and 41 transmit only one half of the input power. This reduces to one half the loading of the gearing and shafting associated with shafts 22 and 41 so that these components can be reduced in size, resulting in a smaller and lighter unit for a given horsepower rating. In addition to this, dividing the transmitted power between the two shafts requires the use of four intermeshing mitre gears in gear box 53. This results in all of these gears being symmetrically loaded, with no bending stresses being generated in the shafting by gear tooth loading. These features are very important with higher horsepower capacity.

FIGURE 4 illustrates drive and steering unit 10a which is slightly different from unit 10. Unit 1011 can be used with large horsepower drives where manual steering would not be practical. In unit 1% this is accomplished by eliminating steering shaft 68 and by substituting for gears 72 and 75 clutches 84 and 85 which form part of the steering mechanism of the unit. Clutch 84 includes a drum 86 fixedly mounted on control shaft 21, while clutch 85 includes a drum 87 fixedly secured to spider 45 of planetary unit 36. Brake bands 89 and 90 surround drums 86 and 87 and are respectively operated in any suitable manner, such as by means of hydraulic units 92 and 93 mounted in casing 11.

When clutches 84 and 85 are engaged, that is, bands 89 and 90 prevent drums 86 and 87 and consequently control shaft 21 and spider 45 from rotating, the drive of the unit functions normally with the angular relationship between power shaft 12 and take-off shaft 60 remaining constant. However, unit 82 or 93 can be operated to disengage clutch 84 or 85 to permit either shaft 21 or spider 45 to rotate, thereby effecting a change in the angular position of the take-off shaft relative to the power shaft. If brake drum 86 is held against rotation, and drum 87 is allowed to turn, the take-off shaft will rotate around axis 23 in one direction, but if drum 87 is held and drum 86 released, the take-off shaft will rotate around said axis in the opposite direction.

FIGURE 5 illustrates another alternative drive and steering unit 10b. In this unit, the planetary epicyclic gear unit 36, tubular shaft 41 and gear 66 have been omitted.

In unit 10]), gear 75b is fixedly secured to the upper end of tubular housing 50 which projects into casing 11 a little above bearing arrangement 51. Gear 75b meshes with idler 76 which, in turn, meshes with gear 77 fixedly mounted on steering shaft 68.

Drive and steering unit 1% operates substantially the same as unit 10. When control shaft 21 is held against rotation, power shaft 12 rotates drive shaft 22 through differential 17, and this has a tendency to rotate take-off shaft 60, gear box 53 and housing 50 around axis 23. The reaction for control shaft 21 is provided by tubular housing 50. The ratio of gears 72 and 73 is such as normally to counterbalance this rotational tendency so that there is zero imbalance torque about steering axis 23 and therefore the angular realtionship of take-off shaft 60 and power shaft 12 normally remains the same. When steering shaft 68 is rotated, control shaft 21 is rotated to cause take-off shaft 60 to rotate around axis 23 in proportion to the degree of rotation of the steering shaft.

What I claim as my invention is:

1. A drive and steering unit comprising a differential mounted for rotation around an axis, differentially rotatable control and drive shafts projecting in opposite directions on said axis from the differential, a power shaft connected to said differential to rotate the latter, a takeoff shaft mounted for angular movement in a plane around said axis, drive means drivingly interconnecting the drive and take-off shafts, and steering means connected to the control shaft and to the take-off shaft normally preventing normal rotation of said control shaft and operable to permit the control shaft to rotate and to cause angular movement on the take-off shaft around said axis.

2. A drive and steering unit comprising a differential mounted for rotation around an axis, differentially rotatable control and drive shafts projecting in opposite directions on said axis from the differential, a power shaft connected to said differential to rotate the latter, a takeoff shaft mounted for angular movement in a plane around said axis, drive means drivingly interconnecting the drive and take-off shafts, steering means connected to the control shaft normally preventing normal rotation of said control shaft and operable to permit the control shaft to rotate, and reaction means connected to the steering means and t0 the take-off shaft and normally preventing operation of said steering means, said reaction means being adapted to permit the steering means to be operated to rotate the control shaft and cause angular movement of the take-off shaft around said axis.

3. A drive and steering unit comprising a differential mounted for rotation around an axis, differentially rotatable control and drive shafts projecting in opposite directions on said axis from the dilferential, a power shaft connected to said differential to rotate the latter, a takeoff shaft mounted for angular movement in a plane around said axis, drive means drivingly interconnecting the drive and take-off shafts, steering means rotatably connected to the control shaft, said steering means when stationary opposing normal rotation of the control shaft and when rotated causing said control shaft to rotate, and reaction means connected to the steering means and to the take-off shaft normally preventing rotation of the steering means by opposing the torque applied thereto by the control shaft, said reaction means being adapted to permit the steering means to be rotated to rotate the control shaft and to cause angular movement of the takeoff shaft around said axis.

4. A drive and steering unit as claimed in claim 3 in which said reaction means comprises a planetary epicyclic gear unit having an internal gear connected to rotate with said differential and surround and meshing with planet gears carried by a spider and arranged around and meshing with a sun gear, a tubular shaft fixedly connected to the sun gear and surrounding said drive shaft, drive means drivingly interconnecting said tubular and take-off shafts whereby the tubular and drive shafts rotate the take-off shaft in the same direction, and means rotatably connecting said steering means and said spider.

5. A drive and steering unit as claimed in claim 4 in which said steering means comprises a steering shaft, first gearing connecting the steering shaft to the control shaft, and second gearing connecting the steering shaft to said spider to rotate the latter oppositely to the direction of rotation of the control shaft when the steering shaft is turned.

6. A drive and steering unit as claimed in claim 3 in which said reaction means comprises a reaction gear surrounding said drive shaft, a rotatable tubular housing surrounding the drive shaft and having an end connected to the reaction gear and an opposite end connected to said take-off shaft so as to be able to rotate the latter around said axis.

7. A drive and steering unit as claimed in claim 6 in which said steering means comprises a steering shaft, first gearing connecting the steering shaft to the control shaft, and second gearing connecting the steering shaft to said reaction gear to rotate the latter oppositely to the direction of rotation of the control shaft when the steering shaft is turned.

8. A drive and steering unit comprising a differential mounted for rotation around an axis, differentially rotatable control and drive shafts projecting in opposite directions on said axis from the differential, a power shaft connected to said differential to rotate the latter, a takeoff shaft mounted for angular movement in a plane around said axis, drive means drivingly interconnecting the drive and take-01f shafts, reaction means connected to the take-off shaft and rotatable therewith when said shaft is rotated around said axis, and steering means individually connected to the control shaft and to the reaction means normally preventing rotation of said control shaft and said reaction means, said steering means being operable selectively to permit the control shaft and the reaction means to rotate.

9. A drive and steering unit as claimed in claim 8 in which said steering means comprises a first normallyengaged clutch connected to the control shaft, first operating means for disengaging said first clutch to permit said control shaft to rotate, a second normally-engaged clutch connected to said reaction means, and second operating means for disengaging said second clutch releasable to permit the reaction means to rotate.

References Cited UNITED STATES PATENTS 2,940,337 6/ 1960 Kalb 74-675 3,013,519 12/1961 Wigger'man -35 3,021,725 2/ 1962 Schneider 74-665 3,094,967 6/1963 Willis 115-35 FRED C. MA'ITERN, JR., Primary Examiner.

ARTHUR T. MCKEON, Examiner. 

1. A DRIVE AND STEERING UNIT COMPRISING A DIFFERENTIAL MOUNTED FOR ROTATION AROUND AN AXIS, DIFFERENTIALLY ROTATABLE CONTROL AND DRIVE SHAFTS PROJECTING IN OPPOSITE DIRECTIONS ON SAID AXIS FROM THE DIFFERENTIAL, A POWER SHAFT CONNECTED TO SAID DIFFERENTIAL TO ROTATE THE LATTER, A TAKEOFF SHAFT MOUNTED FOR ANGULAR MOVEMENT IN A PLANE AROUND SAID AXIS, DRIVE MEANS DRIVINGLY INTERCONNECTING THE DRIVE AND TAKE-OFF SHAFTS, AND STEERING MEANS CONNECTED TO THE CONTROL SHAFT AND TO BE TAKE-OFF SHAFT NORMALLY PREVENTING NORMAL ROTATION OF SAID CONTROL SHAFT AND OPERABLE TO PERMIT THE CONTROL SHAFT TO ROTATE AND TO CAUSE ANGULAR MOVEMENT ON THE TAKE-OFF SHAFT AROUND SAID AXIS. 